Pathology of bronchial asthma and animal models of asthma.

We reviewed studies on pathology of status asthmaticus, asymptomatic asthma, and of animal models developed to study the pathogenesis of asthma. In status asthmaticus airway occlusion by mucous plugs, desquamed epithelium, goblet cell hyperplasia, submucosal glands hypertrophy, increased smooth muscle, basal membrane thickening, inflammatory infiltration of the bronchial mucosa are observed, together with focal areas of alveolar wall destruction in lung parenchyma. At variance with active asthma, in which almost invariably inflammatory cells infiltrate the mucosa, only scarce airway inflammation is reported in asthmatics between attacks. The majority of the animal models developed so far have been addressed to investigate the mechanism of the transient hyperreactivity that is associated with exacerbations of asthma, while little information is available on the structure-function relationship on long-lasting hyperresponsiveness.